Collagenase ointment has been available in the United States as Collagenase Santyl.RTM. Ointment (Advance Biofactures Corp., Lynbrook, N.Y. 11563) for 27 years. It has been used on millions of patients. The concentration of collagenase in Santyl.RTM. Ointment has been no greater than 300 ABC units per gram of ointment. Collagenase ointment has also been available in other countries. It is useful for the debridement of burns and of dermal ulcers, particularly bed sores (decubitus ulcers). The debridement of these lesions is necessary to remove dead and dying tissue that is typically a source of microbial infection. In addition, healing does not take place until this necrotic material is removed. Speed of debridement is thus a therapeutic desideratum.
Collagenase ointment has not been so widely accepted by the burn centers in the treatment of third degree burns as perhaps its efficacy deserves. This lack of acceptance is largely due to the perception that third degree burns in particular require a more rapid debridement than the collagenase ointment can provide. A more rapid debridement of severe burns without the necessity for anesthesia or a surgical operation would constitute a therapeutic advancement.
A more rapid debridement would also be useful in the treatment of dermal ulcers since it wold provide a superior cost/benefit profile.
Dextrans are polysaccharides produced by certain bacteria (e.g. Leuconostoc mesenteroides) and consist of chains of .alpha.-D-glucopyranosyl residues linked predominantly by .alpha.-(1.fwdarw.6)-linkages, with a small fraction of .alpha.-(1.fwdarw.3)-linkages which give rise to chain branching. Dextrans are available in various molecular-weight fractions. Dextran fractions with weight average molecular weights of 40,000, 70,000 and 75,000 daltons have found therapeutic uses as plasma volume expanders. The 40,000-dalton fraction is also used as a blood flow adjuvant. [Ref. Merck Index, Tenth Edition, #2911] In addition, dextran is used in lubricant eye drops and hysteroscopy fluids. [ref. PDR, 45th edition, 1991]
Dextrans are commercially available as a fine white powder that is approved for pharmacological use. The powder absorbs water readily and hence is useful as a drying agent for wounds, and is completely soluble in sufficient amounts of water.
Pharmacologically active ingredients such as enzymes, antibiotics, antifungals, anti-inflammatories, antipyritics, etc. are usually diluted with an excipient for topical use as creams, ointments, lotions, solutions, etc. Many such excipients decrease the shelf life of drug substances.